Analysis of rotating fan in room in ansys fluent
 

Hello !
I am willing to analyze fan rotation in fluent for converged solution in transient manner until it is statistically steady so that i can apply ffowcs williams hawking's model to find the noise created by fan blades(aerodynamically generated noise).I have studied that Moving Reference Frame and Sliding mesh
are methods for such kind of analysis. Would someone please explain me the theory behind these methods?
I have an manual suggesting to first use M.R.F for steady analysis and then use sliding mesh method for transient analysis by feed the solution of steady analysis to this and changing some set up conditions.Is it a right way to do this ? Is having steady analysis before transient in this case is important?
It would be quite helpful if someone help me with the boundary conditions also.
Thanking you in anticipation.